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New technology for aluminum production promises zero CO2 emission

147 points by dagurp 6y ago

bufferoverflow 6y ago
Sounds like bullshit. Doesn't most of CO2 (in aluminum production) come from all the production of electricity that you need to smelt?
- probablypower 6y ago
  You will notice that this article is from an icelandic newspaper. The electricity in Iceland is almost exclusively 'sustainable' energy (hydro and geothermal) and the Icelandic power system is one of the least carbon intensive in the world. At present it is #2 (https://www.electricitymap.org https://www.electricitymap.org) in the world behind Norway at 28 gCO2e/kWh. Smelting aluminium in Iceland instead of say, the USA (~ 400 gCO2e/kWh), is already a great way to reduce the carbon intensity of aluminium products. This article is discussing the CO2 emissions related to some integral processes within the smelter, and it is a big deal. No, it wont save the world, but also no, it is not bullshit. These are the sort of small incermental improvements that we require in ALL industries in order to dent global carbon emissions.
  - chrisco255 6y ago
    Correct me if I'm wrong, but geothermal is only useful in volcanically active regions, right?
    - deleted 6y ago
      [deleted]
    - TheRealPomax 6y ago
      wrong, but it's worth finding out why that's an incorrect assumption on your own. Don't trust comments on the internet.
      - cwal37 6y ago
        That's a bad response when any comment could easily link to a relevant white paper. GP, MIT+INL had a nice report in 2006[1] covering a lot about that and the resource potential. The GeoVision[2] report and data from DOE is also a good and more recent project. [1] https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-Future-of-Geothermal-Energy.pdf https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-... [2] https://www.energy.gov/eere/geothermal/geovision https://www.energy.gov/eere/geothermal/geovision
    - philwelch 6y ago
      There are other forms of carbon-neutral electricity—hydroelectric, solar, wind, tidal, nuclear; you can even capture carbon emissions from natural gas plants if there was a hard requirement to. Since we have to solve that problem anyway it’s a separate problem. Also, aluminum and bauxite can be shipped to/from where it makes the most sense to process it.
  - SV_BubbleTime 6y ago
    This is all true, Iceland is the worlds aluminum smelting hub. And the CO2 here is for the process. However... what people fail to realize over and over is that the route for most of the worlds aluminum is from China to Iceland to China again. In tankers burning fuel like there is no tomorrow. The biggest gain would be in how to refine the aluminum without shipping across the world twice.
    - ClumsyPilot 6y ago
      There are only two options i can think of, bith of them are daynting: massive transmission line across the oceans, or nuclear powered cargo ships.
      - VBprogrammer 6y ago
        Probably not a very popular option but Chinese nuclear power stations would also do the job.
        ClumsyPilot 6y ago
        Thats actually a reasonable point, and china is on nuclear power builsing -spree.
    - sacred_numbers 6y ago
      Tankers are extremely energy efficient. A round trip journey from Reykjavik to Shanghai would consume about 90 kg of fuel per ton transported. Since 2 tons of alumina is converted to about 1 ton of aluminum, the round trip cost for aluminum is 135 kg of fuel, which generates about 420 kg of CO2. If the aluminum were produced using electricity from coal it would generate about 14,000 kg of CO2. Of course, China wouldn't have to use coal if they chose not to, and cargo ship bunker fuel produces some very nasty pollution besides CO2, but in the world we live in it is far better for carbon emissions and probably for the environment in general, to use Iceland as the aluminum smelting hub.
    - DavidPeiffer 6y ago
      >The biggest gain would be in how to refine the aluminum without shipping across the world twice. Yes, that'd be nice. People are working on solutions, but the only economically viable way to refine the material is to use a highly intensive electrolysis process. My quick google search is showing 17,000 kWh/ton of aluminum [1]. It's currently economically viable to refine in Iceland, but China is the #1 producer of raw aluminum [1] [2]. Iceland only has 3 smelters, and the combined capacity is less than the 9 largest smelters in the world, 2 of which are in China. Citation [1] also has mentions of how much better the process of smelting has become. >So, within 60 years, by improving the technology, fluoride emissions have been reduced more than 15 times (Table 2) and annual amounts of fluorinated residues have decreased from 1500 ton after WWII to 60 ton today. From a purely energy standpoint, raw aluminum production has become vastly more efficient [4], with kWh/kg dropping from ~27 in 1940 to ~17 in 2000. The theoretical minimum is 5.99 kWh/kg [5] [1] https://www.sciencedirect.com/topics/engineering/aluminum-production https://www.sciencedirect.com/topics/engineering/aluminum-pr... [2] https://en.wikipedia.org/wiki/List_of_countries_by_primary_aluminium_production https://en.wikipedia.org/wiki/List_of_countries_by_primary_a... [3] https://en.wikipedia.org/wiki/List_of_aluminium_smelters https://en.wikipedia.org/wiki/List_of_aluminium_smelters [4] https://www1.eere.energy.gov/manufacturing/resources/aluminum/pdfs/al_theoretical.pdf https://www1.eere.energy.gov/manufacturing/resources/aluminu... (page 40 of the PDF, numbered 25 on the page) [5] https://www.aceee.org/files/proceedings/2003/data/papers/SS03_Panel1_Paper02.pdf https://www.aceee.org/files/proceedings/2003/data/papers/SS0...
  - twic 6y ago
    > This article is discussing the CO2 emissions related to some integral processes within the smelter In slightly more (but still high school level!) detail, the raw material for aluminum refining is Al2O3. That is dissolved in a bath of molten salt, where the ions dissociate. The 2 Al3+ is electroplated out by adding electrons at the cathode. The 3 O2- comes out by withdrawing electrons at the anode; usually, the anode is carbon [1], and the reaction is: 2 O2- + C -> CO2 + 4 e- The innovation here is to use an inert anode, so the reaction is: 2 O2- -> O2 + 4 e- The fundamental chemistry of this is pretty obvious, so presumably there are good practical reasons why everyone was using carbon anode before. EDIT It seems [2] that the process is using the carbon to do some of the energetic work of reducing the oxygen (carbon loves to reduce oxygen even when it doesn't have two extra electrons, a fact exploited in an earlier industrial process [3]), therefore requiring less electrical energy. This is sort of a way to stealthily burn some carbon to produce energy. [1] https://en.wikipedia.org/wiki/Prebaked_Consumable_Carbon_Anodes https://en.wikipedia.org/wiki/Prebaked_Consumable_Carbon_Ano... [2] https://chemistry.stackexchange.com/questions/6774/why-do-they-use-graphite-anodes-in-the-hall-heroult-process https://chemistry.stackexchange.com/questions/6774/why-do-th... [3] https://en.wikipedia.org/wiki/Fire https://en.wikipedia.org/wiki/Fire
    - catalogia 6y ago
      Do you know how they might be dealing with the oxygen? I assume it comes out very hot and ready to oxidize stuff. I suppose there are stainless alloys that can cope with it?
    - twic 6y ago
      Re-reading this, I realise I've got the bit about carbon reducing oxide ions wrong. The oxide ions are being oxidised here, not reduced. But ending up at CO2 rather than O2 means they don't need to be oxidised as hard - oxygen in CO2 is a bit more reduced than in O2. I think. I probably wouldn't pass A level chemistry if I sat the exams today. When neutral carbon and oxygen react, the carbon reduces the oxygen because it gives it a fractional share of its electrons when they form a bond. But when oxygen is charged, it already has lots of electrons. In this reaction the carbon is helping oxidise the oxide ions.
  - diroussel 6y ago
    Also worth noting that the ore is shipped from Australia and other places to the nordics to get the cheaper smelting. But these large ships are not subject to regulation of emmistions or fuel in international waters. And so they burn bitumen like oil fractions that are very cheap.
- LargoLasskhyfv 6y ago
  Not for their location, they have 99,9% electricity by geothermal and hydroelectric, as in renewable. That is what makes it economical to ship bauxite from all over the world there, and have it manufactured to aluminum, and exported. So this is a nice topping on the cake, to have even some of the last bits of CO2 from the process eliminated. I don't see why this wouldn't apply to other sites elsewhere. How they generate their elictricity is another matter.
  - ajross 6y ago
    Right. Really what this article is about is a "technology" for "exporting" renewable electricity generation, which is a resource Iceland has in spades but has traditionally been hard to transport. And it sounds like a great idea to me. It's just not particularly interesting from the perspective of aluminum smelting.
  - pengaru 6y ago
    Now if only we could get the externalities of burning all that bunker fuel shipping the bauxite paid for up front...
    - mhandley 6y ago
      One possible solution there would be Green Ammonia, which Iceland is also well placed to produce: https://royalsociety.org/topics-policy/projects/low-carbon-energy-programme/green-ammonia/ https://royalsociety.org/topics-policy/projects/low-carbon-e...
    - thinkcontext 6y ago
      I definitely agree that all externalities should be paid for but the co2 emissions from shipping are very low compared to producing aluminium from coal. This comment puts it at 3% https://news.ycombinator.com/item?id=23632148 https://news.ycombinator.com/item?id=23632148
      - pengaru 6y ago
        Which would be great if co2 were all they emitted, burning bunker fuel is very dirty. Of all forms of emissions co2 is relatively harmless.
- gimmeThaBeet 6y ago
  Yes that's true. But as others have mentioned, there is a tendency to situate aluminum smelting in places with hydroelectric power (Brazil, Canada, etc.) if they have it, either for the environmental factor, just the fact you have a large source of power to use and it can't move. I think if an entity is trying to tackle sustainability, to some extent any innovation is innovation. If you try to swing for the fences every time no one may ever get on base.
- Taniwha 6y ago
  depends - the alumina->Al part of Al production is often done in places with cheap, reliable electricity sources. Here in New Zealand it's all hydro power, no carbon emissions, but essentially burning carbon electrodes on the Al pot lines into CO2 is 5% of our national carbon emissions
DavidPeiffer 6y ago
I'm not certain the differences, but there's been a similar effort as a joint venture between Alcoa, Rio Tinto, and Apple to clean up the aluminum smelting process. [1] The aluminum industry is notorious for having incredibly high energy requirements, and being price sensitive to changes in energy contracts. The economics behind smelters are challenging and at an unimaginable scale. Having an electricity interruption of more than a handful of hours can cause the aluminum in-process to solidify, causing tens of millions of dollars in damage to the smelter and requiring months to fix. This paper [2] describes a framework for making decisions to enter/exit a market based on variability of inputs, investment required to exit/enter, etc. While the example in the paper is focused around renewable energy, it can be applied to other types of facilities. We covered this paper for about 2 weeks during undergrad, which at the time was painful, but it was one of the most interesting papers and concepts I've read. A great video outlining the refining process is available in [3]. Having worked there, I promise the safety at Alcoa is now far superior to what's shown in the video. Paul O'Neill hadn't become CEO yet [4]. [1] https://www.apple.com/newsroom/2018/05/apple-paves-the-way-for-breakthrough-carbon-free-aluminum-smelting-method/ https://www.apple.com/newsroom/2018/05/apple-paves-the-way-f... [2] https://www.imse.iastate.edu/wp-content/blogs.dir/16/files/2012/11/tee-mlw-061212.pdf https://www.imse.iastate.edu/wp-content/blogs.dir/16/files/2... [3] https://www.youtube.com/watch?v=J5wPJp-hasU https://www.youtube.com/watch?v=J5wPJp-hasU [4] https://www.forbes.com/sites/roddwagner/2019/01/22/have-we-learned-the-alcoa-keystone-habit-lesson/#1405482858ba https://www.forbes.com/sites/roddwagner/2019/01/22/have-we-l...
- philipkglass 6y ago
  Alcoa and other big aluminum producers have been interested in eliminating the carbon anodes from aluminum smelting for decades, well before global warming concerns rose to the forefront. It is a very difficult problem to make inert anodes efficient and stable enough for long term industrial use. I hope that these recent advancements are enough to start replacing carbon anodes in commercial plants. Some of the non-CO2 reasons to eliminate carbon anodes: - Carbon anodes oxidize while they are in use. Their shape and size changes over time as they erode, and the pot has to be shut down to replace ones that are too worn. - The oxidation of carbon anodes contributes part of the energy needed to transform aluminum oxide into metallic aluminum, but their embedded energy content is much more expensive than the electricity smelters use. The combined materials + electricity cost to produce a ton of aluminum would be lower if efficient, stable inert anodes could be developed. - The oxidation of carbon anodes, ideally, produces pure carbon dioxide. But in actual operating conditions the anode oxidation also produces toxic gases like carbonyl fluoride and carbon monoxide as minor byproducts. Safety systems and processes to prevent toxic gas exposure of workers make it more expensive to build and operate smelters than if the byproduct gas were oxygen.
hannob 6y ago
I feel this is one of those articles where lots of important information is missing. Do they have any expectations on how expensive this process will be? Is there a chance that it's cheaper than existing processes or will it cost more? Is this plant they plan to build subsidized? Do they have plans to enforce this technology? Ultimately for every green technology there's a simple truth: It's only going to be successful if a) it's cheaper than existing technology or b) it's going to be required or incentivized by law. I've been seeing too many articles about fancy new green technologies that promise so much. The problem is: Most of them never happen at scale. Because they're usually more expensive and there's no political will to enforce them.
- philwelch 6y ago
  A surfeit of technical solutions and a lack of social and political solutions define our age.
- dagurp 6y ago
  Unfortunately this is the only article I can find in English. I recommend looking at the youtube video I already posted. They claim it will run at a lower temperature and use less space.
hinkley 6y ago
I just caught a video the other day about manufacturing on the moon. He referred to this kind of research being a potential game changer for lunar colonization. There are many metal oxides on the moon, and if you were trying to construct a habitat then a reduction reaction gives you industrial feedstocks and Oxygen to breathe. But electrolytic refinement of aluminum produces CO2 via the sacrificial anode, so you need a different chemistry to avoid that, or a steady graphite supply and a lot of photosynthesis. He also mentioned that you can use electrolysis to refine iron, but that we have cheaper (but much heavier) terrestrial options.
- travisporter 6y ago
  Would love to watch it! Is there a good youtube channel or book for this sort of ISRU stuff? The ones I have found are too hand-wavy
  - hinkley 6y ago
    Pretty sure this is the one: https://www.youtube.com/watch?v=-dL28N5yPmQ https://www.youtube.com/watch?v=-dL28N5yPmQ (October 2018)
  - DavidPeiffer 6y ago
    NASA Swamp Works does a lot of research on setting up a moon base, mining on the moon, etc. They also sponsor the NASA Lunabotics Competition (formerly NASA Robotic Mining Competition), in which collegiate teams build robots to collect material in an environment very similar to the moon. Philip Metzger is a great follow in Twitter. He was previously at Swamp Works before moving to an academic role. https://twitter.com/DrPhiltill?s=20 https://twitter.com/DrPhiltill?s=20 https://technology-ksc.ndc.nasa.gov/featurestory/swampworks https://technology-ksc.ndc.nasa.gov/featurestory/swampworks https://youtu.be/60v5iIkx-ZU https://youtu.be/60v5iIkx-ZU
  - haldora 6y ago
    I helped write a report [1] about the state of the Space Resources industry for 2019. This report should get you up to speed on the science, engineering, and law/policy going on in the field. Our website specifically covers ISRU, including a monthly newsletter and sporadic articles (including one published this morning about minimizing lunar dust kick-up when landing vehicles on the Moon). [1] https://www.thespaceresource.com/news/2020/the-space-resource-report https://www.thespaceresource.com/news/2020/the-space-resourc...
jeffdavis 6y ago
"using multiple, vertical inert metal-alloy anodes and ceramic cathodes" What is the process? Why was it hard before, and why does it work now? I'm not expecting a thorough analysis, but the article was very light on what they are actually doing, even for a casual reader.
- thepangolino 6y ago
  Could be a matter of finding the right alloys to act as catalyst.
- brennanpeterson 6y ago
  Well, you are convertible AlOx to Al. The current process is AlOx+C+energy ->Al + CO2. This is practical for various reasons. You can directly do AlOx+energy ->Al+O2. This is the proposal, and it works, somewhat. I am not sure this needed to be in the article, as the balance between 'too basic' and 'sufficient' is tricky.
awinter-py 6y ago
> Iceland’s three aluminum smelters ... emit more than 1.6 million tons of CO2 a year ... 30 percent of Iceland’s total CO2 emissions this presumably doesn't include the volcanoes, which globally emit hundreds of millions of tons per year per this https://www.forbes.com/sites/startswithabang/2017/06/06/how-much-co2-does-a-single-volcano-emit/ https://www.forbes.com/sites/startswithabang/2017/06/06/how-...
- Lavery 6y ago
  Unfortunately, the volcanoes have thus far resisted public pressure to reform.
- catalogia 6y ago
  Yes well plugging volcanoes up is a bad idea.
wolfi1 6y ago
When I read the headline I thought to myself: Great, the tackled the overvoltage problem successfully. In electrolysis there are two parameters relevant: the current and the voltage applied. (An electrochemist once told me: voltage means costs, current means money). The current is directly proportional to the amount aluminum (in this case) produced, whereas the applied voltage is directly proportional to the energy involved in the process. So a minimization of the applied voltage means a huge increase in efficiency. But I was mistaken. I hope that these new electrodes are not consumed in the process, otherwise this would mean the overall efficiency would be greatly reduced and if that really means a reduction of carbon emission remains to be seen
Taniwha 6y ago
This would drop 5% of New Zealand's carbon emissions too
mrfusion 6y ago
How much energy is one soda can’s worth of aluminum?
- philipkglass 6y ago
  It's about 14.9 grams of aluminum: https://recycleusainc.com/how-many-aluminum-cans-equal-1-pound/ https://recycleusainc.com/how-many-aluminum-cans-equal-1-pou... Modern aluminum smelters consume 12,500 to 15,000 kilowatt hours per metric ton of metal produced: https://agmetalminer.com/2015/11/24/power-costs-the-production-primary-aluminum/ https://agmetalminer.com/2015/11/24/power-costs-the-producti... If we take the higher value of 15,000 kWh, that's (14.9 / 1000000) * 15000 = 0.22 kWh for one can's worth of aluminum.
  - mrfusion 6y ago
    Thanks! Wow that’s a lot of energy.
    - e_y_ 6y ago
      But when you're done with it, you can just dump it in your Mr. Fusion and get it right back.
    - caf 6y ago
      Enough to drive a Model 3 about 1.5km.
    - perilunar 6y ago
      Fortunately it's 100% recyclable.
dagurp 6y ago
Here is their pitch from 2015 https://www.youtube.com/watch?v=LyJCS1sldhg https://www.youtube.com/watch?v=LyJCS1sldhg
rmm 6y ago
As my mining engineer lecturer always said. Aluminum is congealed electricity. This is a great breakthrough, but unless we reduce the energy requirements, for most countries it wont be a big change.
- rswail 6y ago
  It changes the production process from producing Al+CO2 to Al+O2. That's a good thing for emissions reduction. The power source for aluminium smelting is a separate question and can be replaced with renewables.
  - Taniwha 6y ago
    sadly not just any renewables - if the power goes off the Al in the pot lines hardens and ruins the hardware ... so solar and wind alone are out - geothermal and hydro (or those mixed with solar/wind) are OK

147 points by dagurp 6y ago

Sounds like bullshit. Doesn't most of CO2 (in aluminum production) come from all the production of electricity that you need to smelt?

probablypower 6y ago
You will notice that this article is from an icelandic newspaper. The electricity in Iceland is almost exclusively 'sustainable' energy (hydro and geothermal) and the Icelandic power system is one of the least carbon intensive in the world. At present it is #2 (https://www.electricitymap.org https://www.electricitymap.org) in the world behind Norway at 28 gCO2e/kWh. Smelting aluminium in Iceland instead of say, the USA (~ 400 gCO2e/kWh), is already a great way to reduce the carbon intensity of aluminium products. This article is discussing the CO2 emissions related to some integral processes within the smelter, and it is a big deal. No, it wont save the world, but also no, it is not bullshit. These are the sort of small incermental improvements that we require in ALL industries in order to dent global carbon emissions.
- chrisco255 6y ago
  Correct me if I'm wrong, but geothermal is only useful in volcanically active regions, right?
  - deleted 6y ago
    [deleted]
  - TheRealPomax 6y ago
    wrong, but it's worth finding out why that's an incorrect assumption on your own. Don't trust comments on the internet.
    - cwal37 6y ago
      That's a bad response when any comment could easily link to a relevant white paper. GP, MIT+INL had a nice report in 2006[1] covering a lot about that and the resource potential. The GeoVision[2] report and data from DOE is also a good and more recent project. [1] https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-Future-of-Geothermal-Energy.pdf https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-... [2] https://www.energy.gov/eere/geothermal/geovision https://www.energy.gov/eere/geothermal/geovision
  - philwelch 6y ago
    There are other forms of carbon-neutral electricity—hydroelectric, solar, wind, tidal, nuclear; you can even capture carbon emissions from natural gas plants if there was a hard requirement to. Since we have to solve that problem anyway it’s a separate problem. Also, aluminum and bauxite can be shipped to/from where it makes the most sense to process it.
- SV_BubbleTime 6y ago
  This is all true, Iceland is the worlds aluminum smelting hub. And the CO2 here is for the process. However... what people fail to realize over and over is that the route for most of the worlds aluminum is from China to Iceland to China again. In tankers burning fuel like there is no tomorrow. The biggest gain would be in how to refine the aluminum without shipping across the world twice.
  - ClumsyPilot 6y ago
    There are only two options i can think of, bith of them are daynting: massive transmission line across the oceans, or nuclear powered cargo ships.
    - VBprogrammer 6y ago
      Probably not a very popular option but Chinese nuclear power stations would also do the job.
      - ClumsyPilot 6y ago
        Thats actually a reasonable point, and china is on nuclear power builsing -spree.
  - sacred_numbers 6y ago
    Tankers are extremely energy efficient. A round trip journey from Reykjavik to Shanghai would consume about 90 kg of fuel per ton transported. Since 2 tons of alumina is converted to about 1 ton of aluminum, the round trip cost for aluminum is 135 kg of fuel, which generates about 420 kg of CO2. If the aluminum were produced using electricity from coal it would generate about 14,000 kg of CO2. Of course, China wouldn't have to use coal if they chose not to, and cargo ship bunker fuel produces some very nasty pollution besides CO2, but in the world we live in it is far better for carbon emissions and probably for the environment in general, to use Iceland as the aluminum smelting hub.
  - DavidPeiffer 6y ago
    >The biggest gain would be in how to refine the aluminum without shipping across the world twice. Yes, that'd be nice. People are working on solutions, but the only economically viable way to refine the material is to use a highly intensive electrolysis process. My quick google search is showing 17,000 kWh/ton of aluminum [1]. It's currently economically viable to refine in Iceland, but China is the #1 producer of raw aluminum [1] [2]. Iceland only has 3 smelters, and the combined capacity is less than the 9 largest smelters in the world, 2 of which are in China. Citation [1] also has mentions of how much better the process of smelting has become. >So, within 60 years, by improving the technology, fluoride emissions have been reduced more than 15 times (Table 2) and annual amounts of fluorinated residues have decreased from 1500 ton after WWII to 60 ton today. From a purely energy standpoint, raw aluminum production has become vastly more efficient [4], with kWh/kg dropping from ~27 in 1940 to ~17 in 2000. The theoretical minimum is 5.99 kWh/kg [5] [1] https://www.sciencedirect.com/topics/engineering/aluminum-production https://www.sciencedirect.com/topics/engineering/aluminum-pr... [2] https://en.wikipedia.org/wiki/List_of_countries_by_primary_aluminium_production https://en.wikipedia.org/wiki/List_of_countries_by_primary_a... [3] https://en.wikipedia.org/wiki/List_of_aluminium_smelters https://en.wikipedia.org/wiki/List_of_aluminium_smelters [4] https://www1.eere.energy.gov/manufacturing/resources/aluminum/pdfs/al_theoretical.pdf https://www1.eere.energy.gov/manufacturing/resources/aluminu... (page 40 of the PDF, numbered 25 on the page) [5] https://www.aceee.org/files/proceedings/2003/data/papers/SS03_Panel1_Paper02.pdf https://www.aceee.org/files/proceedings/2003/data/papers/SS0...
- twic 6y ago
  > This article is discussing the CO2 emissions related to some integral processes within the smelter In slightly more (but still high school level!) detail, the raw material for aluminum refining is Al2O3. That is dissolved in a bath of molten salt, where the ions dissociate. The 2 Al3+ is electroplated out by adding electrons at the cathode. The 3 O2- comes out by withdrawing electrons at the anode; usually, the anode is carbon [1], and the reaction is: 2 O2- + C -> CO2 + 4 e- The innovation here is to use an inert anode, so the reaction is: 2 O2- -> O2 + 4 e- The fundamental chemistry of this is pretty obvious, so presumably there are good practical reasons why everyone was using carbon anode before. EDIT It seems [2] that the process is using the carbon to do some of the energetic work of reducing the oxygen (carbon loves to reduce oxygen even when it doesn't have two extra electrons, a fact exploited in an earlier industrial process [3]), therefore requiring less electrical energy. This is sort of a way to stealthily burn some carbon to produce energy. [1] https://en.wikipedia.org/wiki/Prebaked_Consumable_Carbon_Anodes https://en.wikipedia.org/wiki/Prebaked_Consumable_Carbon_Ano... [2] https://chemistry.stackexchange.com/questions/6774/why-do-they-use-graphite-anodes-in-the-hall-heroult-process https://chemistry.stackexchange.com/questions/6774/why-do-th... [3] https://en.wikipedia.org/wiki/Fire https://en.wikipedia.org/wiki/Fire
  - catalogia 6y ago
    Do you know how they might be dealing with the oxygen? I assume it comes out very hot and ready to oxidize stuff. I suppose there are stainless alloys that can cope with it?
  - twic 6y ago
    Re-reading this, I realise I've got the bit about carbon reducing oxide ions wrong. The oxide ions are being oxidised here, not reduced. But ending up at CO2 rather than O2 means they don't need to be oxidised as hard - oxygen in CO2 is a bit more reduced than in O2. I think. I probably wouldn't pass A level chemistry if I sat the exams today. When neutral carbon and oxygen react, the carbon reduces the oxygen because it gives it a fractional share of its electrons when they form a bond. But when oxygen is charged, it already has lots of electrons. In this reaction the carbon is helping oxidise the oxide ions.
- diroussel 6y ago
  Also worth noting that the ore is shipped from Australia and other places to the nordics to get the cheaper smelting. But these large ships are not subject to regulation of emmistions or fuel in international waters. And so they burn bitumen like oil fractions that are very cheap.
LargoLasskhyfv 6y ago
Not for their location, they have 99,9% electricity by geothermal and hydroelectric, as in renewable. That is what makes it economical to ship bauxite from all over the world there, and have it manufactured to aluminum, and exported. So this is a nice topping on the cake, to have even some of the last bits of CO2 from the process eliminated. I don't see why this wouldn't apply to other sites elsewhere. How they generate their elictricity is another matter.
- ajross 6y ago
  Right. Really what this article is about is a "technology" for "exporting" renewable electricity generation, which is a resource Iceland has in spades but has traditionally been hard to transport. And it sounds like a great idea to me. It's just not particularly interesting from the perspective of aluminum smelting.
- pengaru 6y ago
  Now if only we could get the externalities of burning all that bunker fuel shipping the bauxite paid for up front...
  - mhandley 6y ago
    One possible solution there would be Green Ammonia, which Iceland is also well placed to produce: https://royalsociety.org/topics-policy/projects/low-carbon-energy-programme/green-ammonia/ https://royalsociety.org/topics-policy/projects/low-carbon-e...
  - thinkcontext 6y ago
    I definitely agree that all externalities should be paid for but the co2 emissions from shipping are very low compared to producing aluminium from coal. This comment puts it at 3% https://news.ycombinator.com/item?id=23632148 https://news.ycombinator.com/item?id=23632148
    - pengaru 6y ago
      Which would be great if co2 were all they emitted, burning bunker fuel is very dirty. Of all forms of emissions co2 is relatively harmless.
gimmeThaBeet 6y ago
Yes that's true. But as others have mentioned, there is a tendency to situate aluminum smelting in places with hydroelectric power (Brazil, Canada, etc.) if they have it, either for the environmental factor, just the fact you have a large source of power to use and it can't move. I think if an entity is trying to tackle sustainability, to some extent any innovation is innovation. If you try to swing for the fences every time no one may ever get on base.
Taniwha 6y ago
depends - the alumina->Al part of Al production is often done in places with cheap, reliable electricity sources. Here in New Zealand it's all hydro power, no carbon emissions, but essentially burning carbon electrodes on the Al pot lines into CO2 is 5% of our national carbon emissions

DavidPeiffer 6y ago

I'm not certain the differences, but there's been a similar effort as a joint venture between Alcoa, Rio Tinto, and Apple to clean up the aluminum smelting process. [1] The aluminum industry is notorious for having incredibly high energy requirements, and being price sensitive to changes in energy contracts. The economics behind smelters are challenging and at an unimaginable scale. Having an electricity interruption of more than a handful of hours can cause the aluminum in-process to solidify, causing tens of millions of dollars in damage to the smelter and requiring months to fix. This paper [2] describes a framework for making decisions to enter/exit a market based on variability of inputs, investment required to exit/enter, etc. While the example in the paper is focused around renewable energy, it can be applied to other types of facilities. We covered this paper for about 2 weeks during undergrad, which at the time was painful, but it was one of the most interesting papers and concepts I've read. A great video outlining the refining process is available in [3]. Having worked there, I promise the safety at Alcoa is now far superior to what's shown in the video. Paul O'Neill hadn't become CEO yet [4]. [1] https://www.apple.com/newsroom/2018/05/apple-paves-the-way-for-breakthrough-carbon-free-aluminum-smelting-method/ https://www.apple.com/newsroom/2018/05/apple-paves-the-way-f... [2] https://www.imse.iastate.edu/wp-content/blogs.dir/16/files/2012/11/tee-mlw-061212.pdf https://www.imse.iastate.edu/wp-content/blogs.dir/16/files/2... [3] https://www.youtube.com/watch?v=J5wPJp-hasU https://www.youtube.com/watch?v=J5wPJp-hasU [4] https://www.forbes.com/sites/roddwagner/2019/01/22/have-we-learned-the-alcoa-keystone-habit-lesson/#1405482858ba https://www.forbes.com/sites/roddwagner/2019/01/22/have-we-l...

philipkglass 6y ago
Alcoa and other big aluminum producers have been interested in eliminating the carbon anodes from aluminum smelting for decades, well before global warming concerns rose to the forefront. It is a very difficult problem to make inert anodes efficient and stable enough for long term industrial use. I hope that these recent advancements are enough to start replacing carbon anodes in commercial plants. Some of the non-CO2 reasons to eliminate carbon anodes: - Carbon anodes oxidize while they are in use. Their shape and size changes over time as they erode, and the pot has to be shut down to replace ones that are too worn. - The oxidation of carbon anodes contributes part of the energy needed to transform aluminum oxide into metallic aluminum, but their embedded energy content is much more expensive than the electricity smelters use. The combined materials + electricity cost to produce a ton of aluminum would be lower if efficient, stable inert anodes could be developed. - The oxidation of carbon anodes, ideally, produces pure carbon dioxide. But in actual operating conditions the anode oxidation also produces toxic gases like carbonyl fluoride and carbon monoxide as minor byproducts. Safety systems and processes to prevent toxic gas exposure of workers make it more expensive to build and operate smelters than if the byproduct gas were oxygen.

hannob 6y ago

I feel this is one of those articles where lots of important information is missing. Do they have any expectations on how expensive this process will be? Is there a chance that it's cheaper than existing processes or will it cost more? Is this plant they plan to build subsidized? Do they have plans to enforce this technology? Ultimately for every green technology there's a simple truth: It's only going to be successful if a) it's cheaper than existing technology or b) it's going to be required or incentivized by law. I've been seeing too many articles about fancy new green technologies that promise so much. The problem is: Most of them never happen at scale. Because they're usually more expensive and there's no political will to enforce them.

philwelch 6y ago
A surfeit of technical solutions and a lack of social and political solutions define our age.
dagurp 6y ago
Unfortunately this is the only article I can find in English. I recommend looking at the youtube video I already posted. They claim it will run at a lower temperature and use less space.

hinkley 6y ago

I just caught a video the other day about manufacturing on the moon. He referred to this kind of research being a potential game changer for lunar colonization. There are many metal oxides on the moon, and if you were trying to construct a habitat then a reduction reaction gives you industrial feedstocks and Oxygen to breathe. But electrolytic refinement of aluminum produces CO2 via the sacrificial anode, so you need a different chemistry to avoid that, or a steady graphite supply and a lot of photosynthesis. He also mentioned that you can use electrolysis to refine iron, but that we have cheaper (but much heavier) terrestrial options.

travisporter 6y ago
Would love to watch it! Is there a good youtube channel or book for this sort of ISRU stuff? The ones I have found are too hand-wavy
- hinkley 6y ago
  Pretty sure this is the one: https://www.youtube.com/watch?v=-dL28N5yPmQ https://www.youtube.com/watch?v=-dL28N5yPmQ (October 2018)
- DavidPeiffer 6y ago
  NASA Swamp Works does a lot of research on setting up a moon base, mining on the moon, etc. They also sponsor the NASA Lunabotics Competition (formerly NASA Robotic Mining Competition), in which collegiate teams build robots to collect material in an environment very similar to the moon. Philip Metzger is a great follow in Twitter. He was previously at Swamp Works before moving to an academic role. https://twitter.com/DrPhiltill?s=20 https://twitter.com/DrPhiltill?s=20 https://technology-ksc.ndc.nasa.gov/featurestory/swampworks https://technology-ksc.ndc.nasa.gov/featurestory/swampworks https://youtu.be/60v5iIkx-ZU https://youtu.be/60v5iIkx-ZU
- haldora 6y ago
  I helped write a report [1] about the state of the Space Resources industry for 2019. This report should get you up to speed on the science, engineering, and law/policy going on in the field. Our website specifically covers ISRU, including a monthly newsletter and sporadic articles (including one published this morning about minimizing lunar dust kick-up when landing vehicles on the Moon). [1] https://www.thespaceresource.com/news/2020/the-space-resource-report https://www.thespaceresource.com/news/2020/the-space-resourc...

jeffdavis 6y ago

"using multiple, vertical inert metal-alloy anodes and ceramic cathodes" What is the process? Why was it hard before, and why does it work now? I'm not expecting a thorough analysis, but the article was very light on what they are actually doing, even for a casual reader.

thepangolino 6y ago
Could be a matter of finding the right alloys to act as catalyst.
brennanpeterson 6y ago
Well, you are convertible AlOx to Al. The current process is AlOx+C+energy ->Al + CO2. This is practical for various reasons. You can directly do AlOx+energy ->Al+O2. This is the proposal, and it works, somewhat. I am not sure this needed to be in the article, as the balance between 'too basic' and 'sufficient' is tricky.

awinter-py 6y ago

> Iceland’s three aluminum smelters ... emit more than 1.6 million tons of CO2 a year ... 30 percent of Iceland’s total CO2 emissions this presumably doesn't include the volcanoes, which globally emit hundreds of millions of tons per year per this https://www.forbes.com/sites/startswithabang/2017/06/06/how-much-co2-does-a-single-volcano-emit/ https://www.forbes.com/sites/startswithabang/2017/06/06/how-...

Lavery 6y ago
Unfortunately, the volcanoes have thus far resisted public pressure to reform.
catalogia 6y ago
Yes well plugging volcanoes up is a bad idea.

wolfi1 6y ago

When I read the headline I thought to myself: Great, the tackled the overvoltage problem successfully. In electrolysis there are two parameters relevant: the current and the voltage applied. (An electrochemist once told me: voltage means costs, current means money). The current is directly proportional to the amount aluminum (in this case) produced, whereas the applied voltage is directly proportional to the energy involved in the process. So a minimization of the applied voltage means a huge increase in efficiency. But I was mistaken. I hope that these new electrodes are not consumed in the process, otherwise this would mean the overall efficiency would be greatly reduced and if that really means a reduction of carbon emission remains to be seen

Taniwha 6y ago

This would drop 5% of New Zealand's carbon emissions too

mrfusion 6y ago

How much energy is one soda can’s worth of aluminum?

philipkglass 6y ago
It's about 14.9 grams of aluminum: https://recycleusainc.com/how-many-aluminum-cans-equal-1-pound/ https://recycleusainc.com/how-many-aluminum-cans-equal-1-pou... Modern aluminum smelters consume 12,500 to 15,000 kilowatt hours per metric ton of metal produced: https://agmetalminer.com/2015/11/24/power-costs-the-production-primary-aluminum/ https://agmetalminer.com/2015/11/24/power-costs-the-producti... If we take the higher value of 15,000 kWh, that's (14.9 / 1000000) * 15000 = 0.22 kWh for one can's worth of aluminum.
- mrfusion 6y ago
  Thanks! Wow that’s a lot of energy.
  - e_y_ 6y ago
    But when you're done with it, you can just dump it in your Mr. Fusion and get it right back.
  - caf 6y ago
    Enough to drive a Model 3 about 1.5km.
  - perilunar 6y ago
    Fortunately it's 100% recyclable.

dagurp 6y ago

Here is their pitch from 2015 https://www.youtube.com/watch?v=LyJCS1sldhg https://www.youtube.com/watch?v=LyJCS1sldhg

rmm 6y ago

As my mining engineer lecturer always said. Aluminum is congealed electricity. This is a great breakthrough, but unless we reduce the energy requirements, for most countries it wont be a big change.

rswail 6y ago
It changes the production process from producing Al+CO2 to Al+O2. That's a good thing for emissions reduction. The power source for aluminium smelting is a separate question and can be replaced with renewables.
- Taniwha 6y ago
  sadly not just any renewables - if the power goes off the Al in the pot lines hardens and ruins the hardware ... so solar and wind alone are out - geothermal and hydro (or those mixed with solar/wind) are OK